Installing Measuring Cells Made Easily

True to the motto «All things seem possible in May», we welcomed a new machine into cell production. Continue reading to find out what we need this machine for and what it can do.

The heart of every pressure transmitter is the measuring cell. The actual pressure sensor is attached to it. Aluminum bonding wires create the connection between the pressure chip and the glass feed-through pins.  Being only 0.025mm thick, the bonding wires are very sensitive.

For this reason, measuring cells are welded into a so-called membrane body. This protects the sensor from external influences. When installing the measuring cells into the membrane body, a good eye and an even better instinct are required. If the measuring cell is not perfectly centered, the bonding wires could touch the edge and be damaged or even destroyed.

To ensure that this procedure works precisely and is suitable for mass production, the process was automated at an early stage. An installation robot developed by KELLER was successfully put into operation many years ago. Over the course of its long life, the affectionately named «Robi» installed measuring cells into the double-digit million range. Increasing numbers of pieces, additional requirements, new products but also advancing technology made life difficult for Robi and forced the machine to its knees.

In October 2021, it was decided that a new machine be built and it should meet the following requirements:

• Installation of >600 measuring cells per hour
• All types of measuring cells and membrane bodies must be able to be processed
• «No» setup time
• Double capacity for longer runtime without operation
• Integrated 100% function test of the measuring cells (saves an additional, upstream test step in production)

20 months and four milestone meetings later, the time had come. On Wednesday, 17 May 2023, the new machine arrived in cell production. All media connections had already been prepared and the space cleared. Two walls had to be temporarily removed for the relocation of the measuring cell installation system, short MZA, from the production equipment building to us. Everything went like clockwork, and we were happy to start unpacking.

Inside the machine, instead of a robot arm, there is now a very fast and precise three-axis system to achieve the ambitious cycle times. The equipment is now located on the left and right of the machine. This eliminates set-up times. As soon as the machine is filled on one side, the table moves into the system and the installation process is started. At the same time, the next order can be prepared on the other side and entered onto the control panel without interrupting production.

The machine meets all the main requirements set and is already a complete success. With so many application-specific requirements and special features, this cannot be taken for granted. Fortunately, KELLER has its own equipment manufacturing department. Not only do they know our products and processes very well, but they are also always nearby, flexible, and very competent.

Often unforeseen problems arise during such projects. In the case of externally procured equipment, this means that the specifications as well as the price must be adjusted. By developing and producing the systems internally, we save money while concentrating on the best possible solution.  We achieved our goal and would like to thank our equipment manufacturing department and all the people involved who contributed in any way to the new MZA.